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1.
Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver 总被引:3,自引:0,他引:3
Sakono M Miyanaga F Kawahara S Yamauchi K Fukuda N Watanabe K Iwata T Sugano M 《Lipids》1999,34(9):997-1000
The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion
were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post-perfused liver
cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA-fed
rats produced significantly more ketone bodies; and the ratio of β-hydroxybutyrate to acetoacetate, an index of mitochondrial
redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol
and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant.
Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced β-oxidation of fatty acids
at the expense of esterification of fatty acid in the liver. 相似文献
2.
Gaofeng Yuan Haiyan Sun Andrew J. Sinclair Duo Li 《European Journal of Lipid Science and Technology》2009,111(6):537-545
The effects of two isomers of conjugated linolenic acid (CLnA), α‐eleostearic acid (α‐ESA) and punicic acid (PA), on body fat and lipid metabolism were investigated, compared with a conjugated linoleic acid (CLA) mixture (primarily cis9,trans11‐ and trans10,cis12‐18:2) and α‐linolenic acid (ALA), a non‐conjugated octadecatrienoic acid, in the present study. ICR mice were fed either a control diet or one of four experimental diets supplemented with 1% α‐ESA, 1% PA, 1% CLA mixture and 1% ALA in the form of triacylglycerols (TAG) for 6 weeks. The weights of perirenal and epididymal adipose tissues were significantly decreased while the liver weight was significantly increased in mice fed CLA, compared with the control. In contrast to CLA, the tissue weights in α—ESA‐, PA‐ and ALA‐fed mice were not affected. No significant differences were observed in TAG, total cholesterol, high‐density lipoprotein and low‐density lipoprotein cholesterol levels among the five groups. The liver TAG level was significantly decreased in mice fed α‐ESA and PA while it was significantly increased in mice fed the CLA mixture. These results indicate that CLnA and CLA have differential effects on body fat mass and liver TAG levels in mice. 相似文献
3.
High fat diets promote the development of mammary tumors induced in rats by 7,12-dimethylbenz(a)anthracene (DMBA), and polyunsaturated
fats are more effective than saturated fats. This difference is related to the linoleic acid content of polyunsaturated vegetable
oils, but the amount of linolealte required for maximum tumor promotion appears to be higher than indicated by earlier experiments.
Comparison of the effects of a polyunsaturated vegetable oil (corn oil) containing linoleate with a fish oilo (menhaden oil)
containing polyunsaturated fatty acids derived from linolenic acid showed that higher dietary mammary tumors, while corresponding
levels of menhaden oil had an inhibitory effect. This is further evidence that promotion of mammary tumorigenesis by polyunsaturated
vegetable oils may be mediated by prostaglandins or other biologically active eicosanoids derived from n−6 fatty acids. 相似文献
4.
Akahoshi A Koba K Ichinose F Kaneko M Shimoda A Nonaka K Yamasaki M Iwata T Yamauchi Y Tsutsumi K Sugano M 《Lipids》2004,39(1):25-30
The effect of the interaction of CLA and type of dietary protein on lipid metabolism was studied in male rats by feeding diets
containing casein (CAS) or soy protein (SOY) as dietary protein and either linoleic acid (LA, a control FA) or graded levels
of CLA at 0,0.1, 0.5, and 1.0% for 28 d. CLA reduced the weight of perirenal adipose tissue in a dose-dependent manner, but
the magnitude of the reduction was greater when rats were fed SOY. Feeding SOY resulted in a significant reduction of the
concentrations of serum total and HDL cholesterol, TG, glucose, and insulin irrespective of dietary CLA. The concentration
of serum leptin tended to be lower on the SOY diet free of CLA than in the corresponding CAS diet, but it fell with an increasing
dietary level of CLA in the CAS groups. In contrast, serum leptin tended to increase when CLA was added to SOY diets. The
concentration of serum adiponectin was higher in the CAS than in the SOY groups, and it tended to increase in response to
dietary CLA levels in the CAS-fed rats, whereas CLA showed no effect in SOY-fed rats. The activity of liver mitochondrial
carnitine palmitoyltransferase was higher in the SOY than in the CAS groups, but it tended to increase with an increasing
dietary level of CLA in both protein groups. Although the body fat-reducing activity of CLA was more effective when the protein
source was SOY, rats fed CAS appeared to be more susceptible to CLA than in those fed SOY with respect to cytokines examined.
These results suggest that the type of dietary protein may modify the antiobesity activity of CLA. 相似文献
5.
Male Sprague-Dawley weanling rats were fed isocaloric diets consisting of 10% (by wt) fat. The six groups differed in the
ratio of corn oil and butter fat present in the diets such that: 10C, 10% corn oil (C); 8C2B, 8% C/2% butter fat (B); 6C4B,
6% C/4% B; 4C6B, 4% C/6% B; 2C8B, 2% C/8% B; and 10B, 10% B. Liver plasma membranes were analyzed for fatty acid composition
and cholesterol/phospholipid molar ratio. The 18∶2n−6 content was constant in the 10C and 8C2B diets and then decreased linearly
through the 2C8B diet. The 20∶4n−6 and 18∶1n−9 contents were constant except in the 10B diet, in which a significant decrease
and increase, respectively, were observed. The cholesterol/phospholipid molar ratio increased between the 10C and 6C4B diets
and subsequently (4C6B and 10B diets) remained constant. This data indicates that changes in n−6 fatty acid content in the
liver plasma membrane are directly related to dietary intake only for 18∶2n−6. Arachidonic acid content in the membrane is
maintained at a constant level until the linoleic acid content of the diet is reduced to 0.5% of calories. It also indicates
that the cholesterol content of the membrane becomes saturated and does not increase with increasing concentrations of saturated
fat in the diet.
Presented in part at the FASEB Meeting, Washington, D.C., April, 1987. 相似文献
6.
It has been reported that consumption of CLA and EPA alters lipid metabolism. CLA contains conjugated double bonds, and EPA
is an n−3 PUFA. Based on the possibility that a molecule with both of these structures might have interesting physiological
effects, we prepared conjugated FA from EPA by alkaline isomerization and examined the effects of the conjugated EPA (CEPA)
on lipid metabolism in rats. Rats were fed by oral gavage every day for 4 wk with 200 mg of FA including linoleic acid, EPA,
CLA, or CEPA. Compared with other groups, rats fed CEPA showed a significant weight loss in epididymal adipose tissue and
significant decreases in the levels of liver TAG and total cholesterol (TC), indicating reduced accumulation of lipid in the
liver and adipose tissue. The plasma levels of TAG, TC, FFA, and tumor necrosis factor-α in rats fed CEPA were reduced, as
was the activity of the FA synthesis system in the liver, whereas the FA-β-oxidation system was activated by CEPA. These results
suggest that intake of CEPA suppresses lipid accumulation in the liver and epididymal adipose tissue while increasing lipid
catabolism in rats. 相似文献
7.
Dietary polyunsaturated fat versus saturated fat in relation to mammary carcinogenesis 总被引:3,自引:0,他引:3
High levels of dietary fat have been shown to promote the development of mammary tumors induced in rats by 7,12-dimethylbenz(α)anthracene,
and polyunsaturated fats were found to be more effective than saturated fats. In further studies it was found that diets containing
3% sunflowerseed oil (polyunsaturated fat) and 17% beef tallow or coconut oil (saturated fats) enhance tumorigenesis as much
as a diet containing 20% sunflowerseed oil. Rats on these diets developed at least twice as many tumors as those fed diets
containing either 3% sunflowerseed oil or 20% of the saturated fats alone. These results are in accord with human epidemiological
data which show that breast cancer mortality in different countries is positively correlated with total fat intake but not
with intake of polyunsaturated fat. Total fat intake varies greatly in different countries, but most human diets probably
contain levels of polyunsaturated fat at least equivalent to 3% sunflowerseed oil. 相似文献
8.
Ingestion of CLA activates β-oxidation and causes loss of body fat in rodents. We investigated the effects of dietary CLA
on endurance capacity and energy metabolism during exercis in mice. Five-week-old male BALB/c mice were fed a control diet
containing 1.0% linoleic acid or a diet containing 0.5% CLA that replaced an equivalent amount of linoleic acid for 1 wk.
The maximum swimming time until fatigue was significantly higher in the CLA-fed group than in the control group. During treadmill
running, the respiratory exchange ratio was significantly lower in the CLA-fed group, but oxygen consumption did not differ
significantly between groups, suggesting that FA contributed more as an energy substrate in the CLA-fed mice. The muscle lipoprotein
lipase activity was significantly higher in the CLA-fed group than in the control group. These results suggest that CLA ingestion
increases endurance exercise capacity by promoting fat oxidation during exercise. 相似文献
9.
Supplementation with CLA: Isomer incorporation into serum lipids and effect on body fat of women 总被引:5,自引:5,他引:0
Animal studies have suggested that CLA, a natural component of meat and dairy products, may confer beneficial effects on health.
However, human studies using supplementation with CLA have produced contradictory results. The aim of the present study was
to further investigate the effect of CLA supplementation on human body fat, serum leptin, and serum lipids, as well as the
incorporation of CLA isomers into serum lipids classes. Sixteen young healthy nonobese sedentary women received 2.1 g of CLA
(divided equally between the cis,trans-9,11 and trans,cis-10,12 isomers) daily for 45 d and placebo for 45 d in a randomized double-blind crossover design. Body fat was estimated
(by measurement of skinfold thickness at 10 sites), and blood was sampled at the beginning, middle, and end of the entire
intervention period; an additional blood sample was obtained 2 wk thereafer. No significant differences in energy, carbohydrate,
lipid, or protein intake existed between the CLA and placebo intake periods. No significant differences were found in body
fat or serum leptin, TAG, total cholesterol, HDL-cholesterol, and alanine aminotransferase between CLA and placebo. The CLA
isomer content of serum TAG, phospholipids, and total lipids increased 2–5 times with CLA supplementation (P<0.05). In contrast, the CLA content of cholesteryl esters did not change significantly. The period of 2 wk after the end
of CLA supplementation was sufficient for its washout from serum lipids. These data indicate that supplementation with 2.1
g of CLA daily for 45 d increased its levels in blood but had no effect on body composition or the lipidemic profile of nonobese
women. 相似文献
10.
Prais Botelho A Santos-Zago LF Costa de Oliveira A 《Archivos latinoamericanos de nutrición》2008,58(2):156-163
Dietary supplementation with conjugated linoleic acid (CLA) may reduce body fat mass and increase lean body mass in various species. The objective of this study was to study the effects of conjugated linoleic acid (CLA) supplementation on body composition, serum leptin and triacylglycerol levels in Wistar rats. Rats received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge CLA, and group CO, supplemented with CLA One) in the concentrations of 2% of daily feed consumption. Serum leptin and triacylglycerol levels of rats were measured by means of commercial kits. After 42 days of supplementation, rats in the control group exhibited body fat contents of 53.94 +/- 6.80 g, and those in groups AE and CO had 45.43 +/- 4.86 g and 43.75 +/- 1.93 g, respectively, corresponding to a mean body fat reduction of 18%. Water, whole body protein and ash contents of rats supplemented with CLA were statistically higher relative to control group content (corresponding to a mean increasing of 7.65%; 6.5% and 12.35%, respectively). Experimental groups AE and CO, which received CLA supplementation, had statistically lower serum leptin levels (3.45 +/- 0.46 ng/mL and 3.08 +/- 0.19 ng/mL, respectively) relative to the control group (4.21 +/- 0.22 ng/mL) which received linoleic acid. Triacylglycerol levels did not change after CLA supplementation (p > 0.05). Supplementation with conjugated linoleic acid in the concentration of 2% of mean daily feed consumption was able to change body composition of rats after 42 days of experimentation. 相似文献
11.
CLA has been shown to induce or suppress excess liver lipid accumulation in various animal models. Interestingly, the state
of insulin resistance may be an important modulator of this effect. The objective of the current study was to determine how
feeding a dietary CLA mixture would affect liver lipid accumulation in insulin-resistant/obese and lean rats in relation to
liver function, lipidemia, liver TAG and phospholipid FA composition, and expression of hepatic markers of FA transport, oxidation,
and synthesis. Six-week-old fa/fa and lean Zucker rats (n=20/genotype) were fed either a 1.5% CLA mixture or a control diet for 8 wk. CLA supplementation reduced liver lipid concentration
of fa/fa rats by 62% in concurrence with improved liver function (lower serum alanine aminotransferase and alkaline phosphatase) and
favorable modification of the serum lipoprotein profile (reduced VLDL and LDL and elevated HDL) compared with control-fed
fa/fa rats. The fa/fa genotype had two-thirds the amount of CLA (as % total FA) incorporated into liver TAG and phospholipids compared with the
lean genotype. In both genotypes, CLA altered the hepatic FA profile (TAG greater than phospholipids) and these changes were
explained by a desaturase enzyme index. Liver-FA-binding protein and acyl CoA oxidase, markers of FA transport and oxidation,
respectively, were expressed at higher levels in CLA-fed fa/fa rats. In summary, these results illustrate a strong relationship between the state of insulin resistance and liver lipid
metabolism and suggest that CLA acts to favorably modify lipid metabolism in fa/fa Zucker rats. 相似文献
12.
The present study examined the antioxidant activity of conjugated octadecatrienoic fatty acid (9 cis, 11 trans, 13 trans-18∶3), α-eleostearic acid, of karela seed (Momordica charantia), fed to rats for 4 wk. The growth pattern of rats and the effect on plasma cholesterol and high density lipoprotein (HDL)
cholesterol and peroxidation of plasma lipid, lipoprotein, eryhrocyte membrane, and liver lipid were measured. Rats were raised
on diets containing sunflower oil mixed with three different levels of conjugated trienoic fatty acid (9c,11t,13t-18∶3) 0.5,2, and 10% by weight; the control group was raised with sunflower oil as dietary oil as the source of linoleic
acid (9c,12c-18∶2). The growth pattern of the three experimental groups of rats showed no significant difference compared to the control
group of rats, but the group with 10% 9c,11t,13t-18∶3 had slightly higher body weight than the control group of rats. Concentrations of total cholesterol, HDL-cholesterol,
and non-HDL-cholesterol in plasma were similar in all four groups. Plasma lipid peroxidation was significantly lower in the
case of 0.5% 9c,11t,13t-18∶3 group than the control group and the 2 and 10% 9c,11t,13t-18∶3 dietary groups as well. Lipoprotein oxidation susceptibility test with 0.5,2 and 10% 9c,11t,13t-18∶3 dietary groups was significantly less susceptible to lipoprotein peroxidation when compared with sunflower oil dietary
group, and the dietary group with 0.5% 9c,11t,13t-18∶3 showed least susceptibility. There was significant lowering in erythrocyte ghost membrane lipid peroxidation in the
0.5,2, and 10% 9c,11t,13t-18∶3 dietary groups compared to the sunflower oil groups. Nonenzymatic liver tissue lipid peroxidation was significantly
lower in the group of rats raised on 0.5% 9c,11t,13t-18∶3, but the groups on 2 and 10% 9c,11t,13t-18∶3 acid did not show any significant difference compared with the control group of rats. 相似文献
13.
Male and female rats were fed diets containing 2% of calories as corn oil or that plus 40% of calories as beef tallow or corn
oil. After 3, 6, 12 and 18 months groups were given 4-14C-cholesterol ip, and feces were collected for 9 days. Just prior to necropsy3H-acetate was administered ip. Samples of serum, liver, heart and carcass were obtained for analysis. Concentrations of fatty
acids and cholesterol, synthesis of those and recovery of ring-labeled steroid are reported. Mortality from acute respiratory
disease was very high in male rats fed beef tallow or low fat diets and very low in those fed the corn oil diet. In females,
only beef tallow diet resulted in a high mortality rate, and this was lower and at a later age than in males. The most notable
effects of age were in relation to fatty acid synthesis and presence of14C-acidic steroid in the carcass. In 3-month-old rats both fats depressed fatty acid synthesis in comparison to the low fat
diet. At later ages beef fat ceased to depress fatty acid synthesis in both sexes. Corn oil continued to depress fatty acid
synthesis up to 12 months in males and 18 months in females. The presence of14C-acidic steroid in carcass was substantial in 6-month-old rats and constituted ca. 40% of recovered14C in 18-month-old rats. The possibility that the increase in acetate incorporation into fatty acids with age in fat feeding
is related to chain elongation rather than de novo synthesis is discussed. Both the presence and amount of acidic steroid
in the carcass are notable and may be of importance in constructing models of cholesterol turnover.
Presented in part at the AOCS Sterol Symposium, April 1970, and the Federation of American Societies for Experimental Biology,
April 1971.
Scientific Series Paper No. 1536, Colorado Agricultural Experiment Station. 相似文献
14.
John K. G. Kramer Najibullah Sehat Michael E. R. Dugan Magdi M. Mossoba Martin P. Yurawecz John A. G. Roach Klaus Eulitz Jennifer L. Aalhus Allan L. Schaefer Youh Ku 《Lipids》1998,33(6):549-558
Pigs were fed a commercial conjugated linoleic acid (CLA) mixture, prepared by alkali isomerization of sunflower oil, at 2%
of the basal diet, from 61.5 to 106 kg live weight, and were compared to pigs fed the same basal diet with 2% added sunflower
oil. The total lipids from liver, heart, inner back fat, and omental fat of pigs fed the CLA diet were analyzed for the incorporation
of CLA isomers into all the tissue lipid classes. A total of 10 lipid classes were isolated by three-directional thin-layer
chromatography and analyzed by gas chromatography (GC) on long capillary columns and by silver-ion high-performance liquid
chromatography (Ag+-HPLC); cholesterol was determined spectrophotometrically. Only trace amounts (<0.1%; by GC) of the 9,11–18∶2 cis/trans and trans, trans isomers were observed in pigs fed the control diet. Ten and twelve CLA isomers in the diet and in pig tissue lipids were
sepatated by GC and Ag+-HPLC, respectively. The relative concentration of all the CLA isomers in the different lipid classes ranged from 1 to 6%
of the total fatty acids. The four major cis/trans isomers (18.9% 11 cis, 13 trans-18∶2; 26.3% 10 trans, 12 cis-18∶2; 20.4% 9 cis, 11 trans-18∶2; and 16.1% 8 trans, 10 cis-18∶2) constituted 82% of the total CLA isomers in the dietary CLA mixture, and smaller amounts of the corresponding cis,cis (7.4%) and trans,trans (10.1%) isomers were present. The distribution of CLA isomers in inner back fat and in omental fat of the pigs was similar
to that found in the diet. The liver triacylglycerols (TAG), free fatty acids (FFA), and cholesteryl esters showed a similar
patterns to that found in the diet. The major liver phospholipids showed a marked increase of 9 cis,11 trans-18∶2, ranging from 36 to 54%, compared to that present in the diet. However, liver diphosphatidylglycerol (DPG) showed a
high incorporation of the 11 cis,13 trans-18∶2 isomer (43%). All heart lipid classes, except TAG, showed a high content of 11 cis,13 trans-18∶2, which was in marked contrast to results in the liver. The relative proportion of 11 cis,13 trans-18∶2 ranged from 30% in the FFA to 77% in DPG. The second major isomer in all heart lipids was 9 cis,11 trans-18∶2. In both liver and heart lipids the relative proportions of both 10 trans,12 cis-18∶2 and 8 trans,10 cis-18∶2 were significantly lower compared to that found in the diet. The FFA in liver and heart showed the highest content of
trans,trans isomers (31 to 36%) among all the lipid classes. The preferential accumulation of the 11 cis,13 trans-18∶2 into cardiac lipids, and in particular the major phospholipid in the inner mitochondrial membrane, DPG, in both heart
and liver, appears unique and may be of concern. The levels of 11 cis,13 trans-18∶2 naturally found in foods have not been established. 相似文献
15.
The purpose of the present study was to investigate the effects of gamma linolenic acid (GLA) on cardiovascular responses
to psychosocial stress (isolation) and to pressor hormones in the genetically borderline hypertensive rat (SHR×WKY). Adult
male SHR×WKY were divided into two groups following five weeks of group housing. One group (GLA) received eight weeks constant
flow osmotic pumps releasing 0.04 mg GLA in olive oil/kg-hr, while the second group received dummy pumps (DUM). One week following
pump implantation, each group was divided into two subgroups and exposed to a four-week experimental period of either continued
group housing (no stress) or isolation (stress). A two-week recovery period of group housing followed the experimental period.
Blood pressure and heart rate were determined weekly by the tail cuff technique. At the end of the recovery period, animals
in the no stress condition were anesthetized and received an arterial cannula for NOR and ANG infusion and direct BP recording.
Then the responses to an ED50 of NOR and ANG were determined. All animals were then killed for determination of heart weight and adrenal weight. All groups
had mean control period systolic BP values ranging from 143–146 mm Hg. In the no stress condition, neither GLA nor DUM altered
BP over the course of the study. However, BP increased in the DUM group durign all four weeks of the isolation period vs the
control period (p<0.01), whereas BP increased only in week 1 in the GLA group (p<0.05). Heart rate increased during stress
in the DUM group (p<0.05), but not in the GLA group. Vascular reactivity to NOR was unaffected by GLA administration. In contrast,
GLA increased the duration of the pressor response to ANG (p<0.01), but tended to decrease the magnitude of the pressor response
(p<0.09) vs DUM. GLA had no effect on heart weight/body weight ratio. Adrenal weight/body weight ratio was lower in the DUM/no
stress group than all other treatment groups.
These data indicate that GLA administration attenuates the cardiovascular responses to chronic stress in animals with a genetic
predisposition to hypertension, in the absence of an effect on resting BP. They also demonstrate a limitation of GLA effect,
in mature animals, to epigenetic pressor factors. Furthermore, GLA action may involve an alteration of the cardiovascular
responses to ANG, but not NOR. These findings suggest that GLA may be useful in preventing the neurogenic triggering of hypertension
by chronic stress in genetically stress-sensitive animals. 相似文献
16.
Male and female weanling rats that were born to dams fed a diet low in linolenic acid received diets of 15% lipids by weight
containing 45% elaidic acid (as trielaidin) and 8.5% or 0.1% linolenic acid for 10 weeks. Four other groups, in which palmitic
or oleic acid replaced elaidic acid in the diet, served as controls. The fatty acid profiles of several lipid classes were
determined in adipose tissue, adrenals, testes, heart and brain. Elaidic acid was incorporated into tissue lipids in varying
degrees, depending on the organ and on the lipid class. Feeding elaidic acid induced no changes in the polyunsaturated fatty
acid (PUFA) profiles of testes lipids but resulted in definite modifications of the PUFA patterns of heart phosphatidylcholine
(PC) and phosphatidylethanolamine (PE). In linolenic acid-deprived rats, arachidonic acid was decreased in PC and linoleic
acid was increased in both PC and PE; 22∶5n−6 was strongly depressed in both PC and PE. In linolenic acid-fed rats, 22∶6n−3
was decreased in PC and PE. These changes, on the whole, were more evident in females, and some also were observed in adrenal
cholesteryl esters but only slightly in brain phospholipids. the apparent inhibition of the biosynthesis of PUFA induced by
dietary elaidic acid appeared to be complex and of greater intensity in the n−6 fatty acid series than in their n−3 homologues. 相似文献
17.
Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component
of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism
in cultured rat hepatocytes. All fatty acids stimulated [2-3H] glycerol incorporation into VLDL lipids and secretion of [3H]-labeled VLDL by hepatocytes. However, the rate of [3H]-labeled VLDL secretion in the presence of nonlabeled stearate (12.8±0.7 pmol/mg protein/4h) was 46, 59, and 22% of that
observed for those treated with myristate, palmitate, and oleate, respectively. [1-14C]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total
VLDL lipids synthesized from [1-14C] stearate, triacylglycerol accounted for 78% as compared to 88–97% of that derived from palmitate, myristate, and oleate.
The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the
rate of apoB synthesis from [35S] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased
the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3±11.9 nm, were
seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5±9.8 and 38.6±6.8 nm,
diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than
those treated with shorter-chain saturated fatty acids. 相似文献
18.
Pilar Luna Manuela Juárez Miguel Angel de la Fuente 《European Journal of Lipid Science and Technology》2007,109(12):1160-1166
The fatty acid composition of 39 mature human milk samples from four Spanish women collected between 2 and 18 weeks during lactation was studied by gas chromatography. The conjugated linoleic acid (CLA) isomer profile was also determined by silver‐ion HPLC (Ag+‐HPLC) with three columns in series. The major fatty acid fraction in milk lipids throughout lactation was represented by the monounsaturated fatty acids, with oleic acid being the predominant compound (36–49% of total fatty acids). The saturated fatty acid fraction represented more than 35% of the total fatty acids, and polyunsaturated fatty acids ranged on average between 10 and 13%. Mean values of total CLA varied from 0.12 to 0.15% of total fatty acids. The complex mixture of CLA isomers was separated by Ag+‐HPLC. Rumenic acid (RA, cis‐9 trans‐11 C18:2) was the major isomer, representing more than 60% of total CLA. Trans‐9 trans‐11 and 7‐9 (cis‐trans + trans‐cis) C18:2 were the main CLA isomers after RA. Very small amounts of 8‐10 and 10‐12 C18:2 (cis‐trans + trans‐cis) isomers were detected, as were different proportions of cis‐11 trans‐13 and trans‐11 cis‐13 C18:2. Although most of the isomers were present in all samples, their concentrations varied considerably. 相似文献
19.
More than half of the U.S. population has a body mass index of 25 kg/m2 or more, which classifies them as overweight or obese. Obesity is often associated with comorbidities such as diabetes, cardiovascular
diseases, and cancer. CLA and chromium have emerged as major dietary supplements that reduce body weight and fat mass, and
increase basal metabolic rate in animal models. However, studies show that CLA induces insulin resistance in mice and in humans,
whereas Cr improves insulin sensitivity. Hence, we designed the present study to examine the combined effect of CLA and Cr
on body composition and insulin sensitivity in a Balb/c mice (n=10/group) model of high-fat-diet-induced obesity. CLA alone lowered body weight, total body fat mass, and visceral fat mass,
the last of which decreased further with the combination of CLA and Cr. This effect was accompanied by decreased serum leptin
levels in CLA-fed and CLA+Cr-fed mice, and by higher energy expenditure (EE) and oxygen consumption (OC) in CLA+Cr-fed mice.
Serum levels of glucose, insulin, the pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6),
as well as insulin resistance index (IRI), decreased with CLA, whereas CLA and Cr in combination had significant effects on
insulin and IL-6 concentrations and IRI. In summary, CLA+Cr decreased body weight and fat mass in high-fat-diet-fed mice,
which may be associated with decreased leptin levels and higher EE and OC. 相似文献
20.
David Kritchevskya Shirley A. Tepper Subramanian Satchithanandam Marie M. Cassidy George V. Vahouny 《Lipids》1988,23(4):318-321
Rats (6 per group) were fed semipurified diets containing either particulate fibers (alfalfa, 10%; cellulose, 10%; bran, 10%),
a soluble ionic fiber (pectin 5%), soluble, nonionic fibers (guar gum, 5%; Metamucil, 10%), a mixed fiber preparation (Fibyrax,
10%, or an insoluble, ionic bile acid-binding resin (cholestyramine, 2%). The control group was fed the unsupplemented diet.
The feeding period, during which diet and water were provided ad libitum, was 28 days.
Compared with the control group, serum total cholesterol levels were increased by more than 10% in rats fed alfalfa and decreased
by more than 10% in rats fed cellulose, guar gum, Fibyrax and cholestyramine. There were no significant differences in percentage
of plasma HDL cholesterol. Serum triglycerides were elevated in the groups fed alfalfa, pectin, guar gum or Fibyrax and reduced
in the group fed Metamucil. Plasma phospholipids were elevated in rats fed alfalfa or bran, unaffected in rats fed pectin
or Metamucil and reduced in the other groups. Liver total cholesterol was elevated in all groups but those fed wheat bran
and cholestyramine. The percentage of liver cholesterol present as ester was elevated in every group except that fed cholestyramine.
Liver triglycerides were reduced in rats fed guar gum or Metamucil and elevated in those fed alfalfa. Liver phospho-lipids
were lowered in the group fed cellulose.
Liver phospholipids were fractionated by thin layer chromatography to give phosphatidylcholine (PC), phosphatidylethanolamine
(PE), sphingomyelin (Sph), lysophosphatidylcholine (LPC) and phosphatidylinositol plus phosphatidylserine (PI+PS). PC was
elevated in all test groups (7–25%); PE levels ranged from 14% below to 0.3% above controls; Sph levels were sharply lower
(20–53%) in all groups. LPC and PI+PS levels were close to the control value in all test groups.
The results demonstrate that different dietary fibers can affect liver phospholipid composition. In view of the critical roles
of phospholipids in many biological reactions, it will be interesting to survey the influence of dietary fiber on phospholipid
spectra of other tissues.
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